1. Field of the Invention
The present invention relates generally to surgical bone clamps and more specifically to devices used to hold and manipulate bone fragments in order to reduce a fracture or osteotomy.
2. Description of Related Art
There are commercially available a number of bone clamping devices that facilitate the open reduction of a bone fracture or osteotomy. Most commonly, these clamps contact the subject bone at the surface directly exposed at the surgical incision and at the corresponding surface on the far side of the bone. After successful repositioning of the bone fragments so that they are in proper alignment, the bone clamps must be removed to provide access for a fixation device, most commonly a bone plate and bone screws. Before applying the bone plate, a malleable template is first placed at the repair site and bent to conform to the bony anatomy. Next, the bone plate is bent to match the shape of the formed template, and then the bent bone plate is applied to the surgical site. If the templating or subsequent forming of the bone plate is not precise, the procedure must be repeated. Once the bone plate adequately conforms to the bone anatomy, it is used to secure the fracture or osteotomy. The bone plate bridges the defect and typically provides a number of apertures to receive bone screws that secure the plate to the bone.
Upon release of the bone clamps to provide clearance for the malleable template or the bone plate, the reduction is left unsecured and frequently shifts due to soft tissue tension or structural compromise due to bone defects at the fracture site. This necessitates the reapplication of the bone clamps and realignment of the bone fragments. Given the trial and error nature of forming the malleable template and bending the bone plate, this sequence may need to be repeated several times before the bone plate is successfully applied so that the bone fragments are secured in proper alignment. Each repeated sequence increases operating room time, increasing blood loss, increasing anesthesia time and thereby increasing risk to the patient of anesthesia complications, and increasing potential iatragenic tissue damage.
Accordingly, attempts have been made to improve upon this challenging and sometimes frustrating surgical procedure. U.S. Pat. No. 5,797,919 to Brinson provides for a bone clamp that holds the bone fragment by clamping diametrically opposed surfaces. The line of clamping is orthogonal to the plane of surgical access, leaving the bone surface at the incision accessible for a template or bone plate. However, because the clamping surfaces approach the bone surface from the sides, a wider incision is required and more soft tissue is displaced and potentially damaged. Additionally, when two such bone clamps are required to urge two bone fragments back into proper alignment, the clamps must be held manually while the template and bone plate are applied. The member of the surgical team holding the bone clamps may become fatigued during the lengthy trial and error stage of bone plate templating, thereby compromising the accuracy of the reduction.
Another attempt to improve on the surgical efficiency of fracture reduction is found in U.S. Pat. No. 5,578,032 to Lalonde. This patent describes a bone clamp with a ratchet locking scissors mechanism that actuates clamping surfaces. The clamping surfaces contact the bone at the incision site on the near and far sides of the bone, thereby minimizing the exposure required. It further describes a connection bar that locks two clamps into a fixed relative position. This apparatus has several disadvantages. First, the scissors mechanism requires all of the manipulation force to be transmitted through a thumb and finger. This greatly limits the amount of distraction and repositioning force that can be applied to the bone fragments. Secondly, the connecting bar, when unlocked so that the bone clamps are movably connected to the connecting bar, only permit translation along a single axis. This motion would only accommodate fractures that are displaced along a single axis and require no rotational or orthogonal translation correction. Such a fracture rarely occurs in practice. Finally, the bone is clamped between two sharp points, which are only adequate for manipulating very small bones, such as the metacarpals and phalanges. Larger contact surfaces are required to forcefully manipulate larger bones.
It would therefore be an improvement in the medical arts to provide a bone setting apparatus that facilitates the rigid holding of a fracture reduction while concurrently providing access for templating and application of a fracture fixation prosthesis, such as a bone plate or intramedullary rod.
It is an object of the invention to provide a bone setting apparatus that allows for unconstrained repositioning and realignment of the bone fragments.
It is a further object of the invention to provide a bone setting apparatus that can be locked to hold a fixed position and alignment between bone fragments.
It is yet a further object of the invention to provide a bone setting apparatus that provides adequate mechanical advantage for manipulating and reducing a fracture.
It is still a further object of the invention to provide a bone setting apparatus that provides clear access for a fracture fixation prosthesis and associated templates thereof.
It is still another object of the invention to provide a temporary clamp to hold a bone plate in position while it is secured to the bone with screws.
It is yet a further object of the invention to increase the efficiency of the surgical procedure for reducing a bone fracture and applying a fracture fixation prosthesis and thereby decrease blood loss, anesthesia time, risk of infection, and iatragenic tissue damage.
In the preferred embodiment, a bone setting apparatus is comprised of two bone clamps and a lockable, articulating connection apparatus. Each bone clamp includes a primary clamping means for manipulating a bone fragment back into a proper position. Additionally, each bone clamp includes a secondary bone clamping means that provides adequate clamping force for maintaining the reduction when the primary clamping means is released. Furthermore, the secondary bone clamping means provides clearance for the positioning and application of a fracture fixation prosthesis (e.g., a bone plate) to maintain the reduction during healing. Moreover, once a fracture fixation prosthesis is positioned adjacent to the bone while the fracture is securely held by the secondary clamping means, the primary clamping means can be used to hold the fracture fixation prosthesis in position while it is secured to the bone by bone screws or the like.
The combination of two bone clamping means provides a unique advantage. The primary bone clamping means has greater surface contact with the bone, thereby permitting greater forces to be applied to manipulate the bone fragments into proper alignment. Once the reduction is accomplished, lesser forces are required to maintain the bone alignment. Thus, the secondary clamping means requires less bone surface contact, thereby increasing the amount of unobstructed bone surface. This increased accessibility to the exposed bone surface permits adequate access for application of a template and fracture fixation prosthesis.
Another advantage of the bone clamp is an independent clamping actuation mechanism and holding surface. Once the bone clamp is secured to the bone fragment, the user can use a full hand grasp to have maximum leverage for manipulating the bone fragments into proper alignment.
Each bone clamp is attached to a rod by a lockable, articulating joint. The joints can be locked so that a fixed position and orientation are secured between the two bone clamps. In their unlocked state, the joints provide for unconstrained repositioning and reorientation between the bone clamps. The joints and the rod together comprise a connection apparatus for the two bone clamps.
The bone clamps and connection apparatus comprise a bone setting apparatus that facilitate the following surgical technique:
(a) securing each bone clamp to a bone fragment using the primary clamping means;
(b) manual reducing and approximating the bone fracture without any spatial constraint;
(c) locking the reduction in position and orientation with the connection apparatus;
(d) applying the secondary clamping means and releasing the primary clamping means, thereby creating clear access to the exposed bone surface;
(e) positioning a fracture fixation prosthesis at the surgical site;
(f) securing the fracture fixation prosthesis by the primary bone clamping means;
(g) securing the fracture fixation prosthesis to the bone by bone screws or the like; and
(h) removing the bone clamps.
In a further embodiment, each bone clamp has only a single bone clamping means. The counter opposed surfaces of the bone clamping means define a plane of clamping that is at an acute angle to the plane of the surgical incision. The acute angle is large enough so that the exposed bone surface is unobstructed for application of a fracture fixation prosthesis. While this apparatus may require a larger incision, it will eliminate the procedural step, in the preferred embodiment described above, of securing a secondary clamping means and releasing a primary clamping means. This increase in surgical efficiency can outweigh the tradeoffs with a larger incision.
In yet another embodiment, the connection apparatus is attached to each bone clamp by a lockable ball and socket joint. A rod extends from each joint. One rod is solid, and the other rod is tubular with a locking means, such as a thumb screw. The solid rod telescopes, or pistons, within the tubular rod, allowing a sliding motion therebetween. This combination of two ball and socket joints and a piston joint permit unconstrained spatial positioning, both translational and rotational, when the joints are unlocked.
It should be appreciated that various combinations of translating and rotating joints may be used to enable unconstrained spatial positioning for two objects attached to the end of a connection apparatus. In the preferred embodiment, the joints attached to one bone clamp simulate a spherical coordinate system by providing two orthogonal rotation axes and one radial translation. In the alternative embodiment described above, the ball and socket joint combined with the telescoping rod also simulates a spherical coordinate system. Similarly, one could provide three orthogonal translating joints to simulate a Cartesian coordinate system, or one could provide one rotation axis and two orthogonal translation axes to simulate a cylindrical coordinate system.
The above, and other objects, features and advantages of the present invention, will become apparent from the following description read in conjunction with the accompanying drawings.